Before packaged semiconductor units are shipped to customers, each unit is electrically tested for ensuring its functionality. As illustrated in FIGS. 1A-1B, semiconductor units are placed in a test socket 115 on a platform of a semiconductor test equipment 120 to be electrically tested. The test socket 115 is typically shaped to fit the semiconductor units for testing. An active body guide 105, labeled as No. 1, controls the positioning of a current semiconductor unit 100. The body guide 105 has a pickup head 110. The semiconductor unit 100 is coupled to the bottom end of the pickup head 110 for placement within the test socket 115. When the active body guide 105 is directly over the test socket 115 of the platform, the pickup head 110 moves down to position the semiconductor unit 100 within the test socket 115 for testing. After the current semiconductor unit 100 is tested, the pickup head 110 picks up the tested semiconductor unit 100, and the next body guide 105′, labeled as No. 2, moves forward, directly above the test socket 115 to test the next semiconductor unit 100′. Each body guide is similarly configured. The testing of each subsequent semiconductor unit cyclically continues as described.
Although faulty semiconductor units can be detected during testing, it is possible that a semiconductor unit can become stuck in the test socket 115 and, as such, can prevent subsequent semiconductor units from being electrically tested. For example, if the semiconductor unit 100 becomes stuck in the test socket 115, the next semiconductor unit 100′ is placed on top of the stuck semiconductor unit 100 and not in the test socket 115, as illustrated in FIG. 1C, resulting in a double semiconductor unit 125. Consequently, the top semiconductor unit 100′ of the double semiconductor unit 125 escapes electrical testing. Other subsequent semiconductor units also escape electrical testing. These “escaped” semiconductor units are shipped untested to customers.
The present invention addresses at least these limitations in the prior art.